ASD/LRFD Manual - American Wood Council

ASD/LRFD MANUAL FOR ENGINEERED Wood Construction
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M8.2 Reference Design Values
General
Bending
As stated in NDS 8.2, SCL products are proprietary
and each manufacturer develops design values appropriate
for their products. These values are reviewed by the
model building codes and published in acceptance reports
and manufacturer’s literature.
Reference design values are used in conjunction with
the adjustment factors in M8.3.
Shear Design
SCL is typically designed and installed as a rectangular
section. Loads near supports may be reduced per NDS
3.4.3.1. However, such load must be included in bearing
calculations. Shear values for SCL products often change
with member orientation.
Bearing
SCL typically has high F c and F c⊥ properties. With
the higher shear and bending capacities, shorter or continuous
spans are often controlled by bearing. The user is
cautioned to ensure the design accounts for compression
of the support material (i.e., plate) as well as the beam
material. Often the plate material is of softer species and
will control the design.
Published bending capacities of SCL beams are determined
from testing of production specimens. Adjustment
for the size of the member is also determined by test.
Field notching or drilling of holes is typically not allowed.
Similarly, excessive nailing or the use of improper
nail sizes can cause splitting that will also reduce capacity.
The manufacturer should be contacted when evaluating a
damaged beam.
Deflection Design
Deflection calculations for SCL typically are similar to
provisions for other rectangular wood products (see M3.5).
Values for use in deflection equations can be found in the
individual manufacturer’s product literature or evaluation
reports. Some manufacturers might publish “true” E values
which would require additional calculations to account for
shear deflection (see NDS Appendix F).
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M8: STRUCTURAL COMPOSITE LUMBER
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